Baby diaper rash is for the nursing mother one of the most enigmatic problems of infant rearing. One of the primary causes of such diaper rash is, of course, that babies frequently wet their diapers and wear the wet diapers for prolonged periods before they are changed. While a few babies tend to cry when wet, many babies do not cry, and the mothers of this latter group of babies are not alerted to the wet diaper condition until the diaper has been worn for a time sufficient to cause diaper rash.
In an effort to reduce the time during which wet diapers are in contact with a baby's skin, mothers often adhere to a specific change of diaper schedule wherein a baby's diapers are changed periodically according to a pre-established timetable. Although such diaper-changing schedules are helpful, a real reduction of time during which urine contacts the baby's skin is not often realized because no prescribed time table can anticipate an individual baby's changeable physical constitution. For example, an infant might wet its diaper immediately after a scheduled change of the diaper and thus, unknown to the mother, be left in a soiled diaper until the next scheduled change of the diaper.
Alarm devices have previously been proposed as a means for informing a parent or attendant that a wet diaper condition has occurred so that the baby's clothing can be changed and its skin cleansed to eliminate the urine/skin contact and reduce the chances of diaper rash. One example of such a proposed alarm device is disclosed in U.S. Pat. No. 3,460,123 of Bass. Bass shows a wet garment alarm system that includes a transmitter for producing a radio signal and a diaper formed with a pair of spaced conductive screens having an electrolyte disposed therebetween. The transmitter is electrically coupled to the screens and adapted to produce a radio signal when the resistance between the screens falls below a predetermined level. In use, the transmitter of Bass is secured to the upper waist portion of an infant's diaper, and the diaper is secured to its wearer with the pair of conductive screens positioned at the crotch portion of the diaper. When the diaper is wet by the wearer, urine flows into the crotch portion of the diaper and electrically bridges the space between the conductive screens thus reducing the resistance between the screens. This reduced resistance, in turn, actuates the transmitter to produce a radio signal for activating a remote alarm to alert a parent or attendant to the wet diaper condition.
Another system for detecting and signaling a wet diaper condition is disclosed in U.S. Pat. No. 4,106,001 of Mahoney, wherein a garment clip houses a moisture detector and alarm. The garment clip is adapted to be clipped onto an exposed edge of a diaper or other garment to be monitored. An elongated strip of material is detachably connected at one end to the clip and is sized to be positioned in a region of the diaper subject to wetness such as, for example, the crotch region. The strip of material includes a pair of embedded spaced electrodes that are coupled to the detector/alarm. When moisture is provided by the wearer of the undergarment, a partial short circuit occurs between the electrodes at some point along the strip of material. This short circuit is detected by the moisture detector, which activates the alarm to provide an audible indication of urination by the infant or wearer.
A similar system is disclosed in U.S. Pat. No. 4,796,014 of Chia, wherein a safety pin with spaced electrical conductors is coupled to a detector and alarm device attached to a diaper. When urine bridges the space between the electrical conductors of the safety pin, a detection circuit is completed, which, in turn, activates the alarm. The Chia device further includes a time delay circuit to ensure that the alarm does not interfere with an infant's normal urination cycle.
While these and similar devices have been somewhat successful in signaling a wet diaper condition, they still tend to exhibit numerous problems and shortcomings inherent in their respective designs. For instance, several of these devices include a pair of conductive electrodes built into the material forming the diaper itself. Such a configuration is shown in the patent of Bass. Obviously, manufacture of these types of diapers can be relatively expensive since special diaper forming machinery must be developed and implemented. Another common problem with prior art devices is that the detecting strips that reside in the diaper are configured as integral non-detachable elements of the detector and alarm circuits. With such a configuration, the entire device often must be discarded when the sensing strip becomes worn, which is inefficient and wasteful. Also, manufacturing the detection devices and alarms in some prior art devices can become complicated and costly. Finally, the mere fact that conductive electrodes must extend into the diaper to detect resistive changes when a baby wets is objectionable to many parents and, under the proper condition, could result in a mild shock to an infant wearer.
Accordingly, there exists a continuing and heretofore unaddressed need for a wet diaper detector and alarm system that is usable with a conventional disposable or non-disposable diaper, is inexpensive to produce, easy and convenient to use, does not necessarily require that conductive electrodes extend into the diaper itself, and that does not require expensive and bulky housings that must be secured to a wearer's garments. It is to the provision of such a wet diaper detector and alarm system that the present invention is primarily directed.